1. Field of the Invention
The present invention relates to a digitizer device with anti-noise and status display which uses a hardware circuit controlled by a software program to eliminate outside noises and show the current status of the digitizer.
2. Description of the Prior Art
A digitizer generally comprises a X-Y grid, a signal emitter which may be a cursor control mouse or stylus and is controlled to project an oscillating signal onto the X-Y grid through a magnetic induction process, X-Y grid selectors which scan the signal induced onto the X-Y grid, am amplifier and filter circuit which processes the signal detected by the X-Y grid selectors into a low frequency signal, an analog/digital converter which converts the low frequency signal into a digital signal, and a microcontroller unit which calculates the digital signal so as to provide a corresponding coordinate value. The X-Y grid, as shown in FIG. 4, has X-axis conductors and Y-axis conductors horizontally or vertically arranged on a board at right angles. These conductors inductively receive the emitting signal of a stylus or mouse and also inductively receive outside frequency (for example: CRT monitor), thereby causing the coordinate value to be unstable. Therefore, this structure of digitizer can not accurately point out the coordinate value. Furthermore, when the coordinate value is read out, it must be displayed through the screen of the host computer.